|Driesche, Roy Van|
Submitted to: Emerald Ash Borer Research and Technology Development Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2010
Publication Date: 7/30/2010
Citation: Duan, J.J., Ulyshen, M., Bauer, L., Gould, J., Driesche, R. 2010. Development of life tables to assess the establishment and population impact of parasitoids for control of the emerald ash borers. Emerald Ash Borer Research and Technology Development Meeting. FHTEF 01:105. Interpretive Summary:
Technical Abstract: Life tables may be used as a quantitative tool to assess the establishment and impact of introduced natural enemies. One of the critical challenges in constructing life tables for concealed insects such as emerald ash borer is to establish cohorts of the pest. The present study investigates and compares several techniques to create egg and larval cohorts of emerald ash borer for evaluation of the population impact of introduced egg and larval parasitoids. These methods involve placing EAB eggs in bark slits on ash tree trunks, caging egg-laying adult EAB, and use of ash twigs or logs infested with EAB eggs, and may be used effectively to assess the contemporaneous contribution of different mortality factors including the introduced hymenopteran parasitoids to EAB population dynamics. Cohorts of approximately 1500 EAB eggs and 300 larvae were established with the three methods mentioned above on 60 ash trees at six selected sites (three treatment sites and three control sites) in Michigan during the summer months of 2008 and 2009. Following the establishment of EAB cohorts at the study sites, over 3,000 individuals of three introduced parasitoids (T. planipennisi, S. agrili, and O. agrili) were released into each of the three treatment sites. Field observations of the 2008 and 2009 cohorts indicated that a high proportion (30 - 70%) of the EAB eggs were preyed upon possibly by ants and other arthropod predators, but parasitism by the egg parasitoid (O. agrili) was low (< 1%). No cohorts of EAB larvae established in the summer 2008 were parasitized by any of the released parasitoids when sampled in the spring of 2009; however approximately 10% of EAB larvae collected in July of 2009 from the randomly selected trees in the parasitoid release sites were successfully attacked by the introduced larval parasitoid T. planipennisi. Additional cohorts of EAB eggs and larvae were established in the summer of 2009, and will be sampled in the summer of 2010 to further measure the impact of the introduced EAB parasitoids. The potential use and implications of these methods in constructing EAB life table for evaluating the establishment and population impact of introduced parasitoids will be discussed.